How is the national electoral register created?

ODIHR, Needs Assessment Mission Report, Czech Republic Parliamentary Elections, 8-9 October 2021, accessed 4 September 2021

“Voter registration is decentralized and passive; however, citizens residing abroad must actively register with the MFA. Municipal authorities administer and update the voter registers using data from the population register that is maintained by the MoI. Voters are automatically included in the voter lists based on the permanent residence. Special voter lists are compiled based on the information provided by corresponding detention centres, prisons or healthcare facilities. Voters may apply for the Absentee Voting Certificates (AVCs) to the municipality of their permanent residence to vote at any other polling station.”